Abstract
The cutaneous lesions in 25 spontaneous cases of porcine exudative epidermitis (EE) were studied. During the first 4 days mild acanthosis, increase of cytoplasmic RNA, enlarged nucleoli, and intercellular oedema in the stratum spinosum with formation of vesicles occur. A PAS-positive, diastase-resistant material accumulates in the stratum intermedium. The keratohyaline granules disappear and parakeratotic horn containing abundant protein-bound SH-groups and lipids is produced.
Beyond 4 days duration acanthosis and the formation of parakeratotic horn with microabscesses are increased. During healing keratohyaline granules reappear and the formation of normal horn cells is resumed.
Acid phosphatase and succinic dehydrogenase are increased in the parakeratotic horn. Lactic acid dehydrogenase is increased in the transitional zone and alkaline phosphatase in the stratum basale.
The observations indicate inhibition in the stratum intermedium of the differentiation of epithelial cells to horny cells. The disease is believed to be of viral origin.